i84 



THE CACTACEAE. 



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Kby to Species — continued. 





continued. 



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A. Areoles spiniferous; ribs not deeply crenate- 

 BB. Stems blight green. 



Margin of stems horny. 



Ribs of stem broad, thin, crenate 7- 



Ribs of stem thick, scarcely crenate S. 



Margin of stems not homy. 



Stigma-lobes branched or forked. 



Spines several; margins of stem nearly straight; stigma-lobes branched. . 9. 

 Spine one; margins of stem undulate; stigma-lobes forked (at least some- 

 times) ^*^- 



Stigma-lobes (so far as known) entire. 



Perianth-segments red or reddish purple. 



Ribs thin, almost wing-hke; perianth-segments Unear 11. 



Joints angular, not winged; inner perianth-segments oblanceolate. . .12. 



Inner perianth-segments white. 



Scales on the ovary few and scattered 13- 



Scales on the ovary brown, large, imbricated. 



Joint-angles strongly tubercled 14- 



Joint-angles scarcely tubercled or not at all. 



Joints somewhat crenate i5- 



Joints not crenate. 16. 



AA. Areoles without spines; ribs very deeply crenate i?- 



1. Hylocereus guatemalensis (Eichlam). • 



Cereus irigonus guatemalensis Eichlam, Monatsschr. Kakteenk. 21: 68. 191 1. 



Stems high-climbing, 3 to 5 ifieters long, stout, mostly 3 -angled, 2 to 7 

 cm. broad, the basal parts often narrow or nearly terete; joints beautifully 

 glaucous or in time becoming more or less greenish; ribs low-undulate, the 

 margins horny, not at all glaucous; areoles 2 cm. apart or less; spines 2 to 4, 2 to 

 3 mm. long, conic, dark, but on seedlings numerous and bristle-like; flowers 3 

 dm. long; outer perianth-segments rose-colored, acuminate; inner perianth- 

 segments lanceolate, acute, white; style yellow, 7 mm. in diameter; stigma- 

 lobes 25, entire; fruit 6 to 7 cm. in diameter, covered with large scales; seeds 

 black. 





H, undatus 

 H. cubensis 



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H. lemairei 





H, monacanihus 



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H. stenopierus 

 H. extensus 



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L 



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H. napoleonis 





H. trigonus 





H. triangularis 

 H. antiguensis 

 H, calcaratus 



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Type locality: Guatemala. 



Distribution: Guatemala. 



We have grown plants from seeds; the seedlings are erect, 4- angled, 



5pines numerous, the bristles white, the cotyledons 15 mm. long. 



Illustration: Monatsschr. Kakteenk. 23: 155, as Cereus trigonus 



guatemalensis. 



Figu 



ows a joint of a plant sent to the New York 

 from Fiscal, Guatemala, by C. C. Deam. 



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reus purpusii (Weingart). 



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Cereus purpusii Weingart, Monatsschr. Kakteenk. 19: 150. 1909. 



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Fig. 261. — Joint of H. 

 guatemalensis. X0.5. 



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stems bluish, climbing, elongate, epiphytic; ribs 3 or 4, with horny margins only slightly 

 undulate; areoles small; spines 3 to 6, short; flowers large, 25 cm. long and nearly as broad when 

 fully expanded ; outer perianth-segments narrow, purplish ; middle perianth-segments golden ; inner 

 perianth-segments broad, white except at the golden tips. 



Type locality: Near Tuxpan, Mexico. 



Distribution: Lowlands of western Mexico. 



We have grown this plant but have not seen the flowers, our descriotion of them being 



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Illustrations: 



Mr. Weingart 



Kakteenk 



3. Hylocereus ocamponis (Salm-Dyck) Britton and Rose, Contr. U. S. Nat. Herb. 12: 429. 1909. 



^ Cereus ocamponis Salm-Dyck, Cact. Hort. Dyck. 1849. 220. 1850. 



Stems Strongly 3-angled, at first bright green, soon glaucous, dull bluish green in age; ribs rather 

 deeply undulate, their margins with a horny, brown border; areoles 2 to 4 cm. apart, borne near the 



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